Service Engine Light Flashing at 100km/h........

Jana Banana · Post by **Jana Banana** » Sun Feb 18, 2007 9:43 pm

While driving up a slight incline on the Highway, at about 100km/h (yup, live in Canada! LOL!), the service engine light began to flash. When I eased off the light went out and stayed off. The van was running fine and the light only comes one at that speed while under slight load due to driving up slight incline etc.

Had a shop read the computer for codes and it came up as "random misfiring" and they recommended a complete tune up. Hubby replaced rotor and cap (which were very obviously in due of replacement upon inspection), plugs, wires, pvc value and cleanout the air filter. Took it back for another drive on the highway and the "dang" service engine light came on again flashing, at the exact same spot - 100km/h under slight load due to slight incline. Light goes out when easing off the gas......

Hubby thinks it could be the transmission slipping and the fluid appears in need of a change, which I will get done tomorrow.

Could this be the problem? Hubby voiced his concern to the tech at the shop this morning where they read the computer for codes and they were certain it was the needed tune up that was causing the problem...........

Any other ideas? TIA!

PS, this is Jana Banana from AstroSafari.com but I can't remember my password and can't seem to get it to send me my password via email :( I've re-registered there but am waiting for it to activate.

ETA: Ok, finally logged into AstroSafari.com - so I've cross posted this there too

astrozam · Post by **astrozam** » Mon Feb 19, 2007 7:48 am

Welcome Jana, one of the best tools you can invest in is a code reader for your van,in your case that would be OBD2 which are for 96 and up.For the shop to profess you need a tune up is kinda a broad stroke,they should certainly be able to read the codes and give those codes to your husband and explain what they mean.If their not willing to be upfront I'd find another shop

It's not Crappy tire is it?

Just for curiosity,is your coolant level low,or engine oil level low?

signed: freezing in Ontario

Jana Banana · Post by **Jana Banana** » Mon Feb 19, 2007 8:09 am

Yah, it was crappy tire - the only shop that was able to hook it up for us yesterday vs. waiting a few more days. This is my daycare van and I need her running well Mon-Fri [-o<

When I asked for the specific code he said it was 300 or 301, he couldn't remember which, and it was "random misfire" - hence their diagnosis of recommended tune up. Forgot to ad in my OP, we also changed the fuel filter.

I'm going to my regular fluid change place today and will be getting an oil and tranny fluid change - I'll get them to check the coolant level too, thx.

V8famvan on Astrosafari.com posted some good info on the exact codes from the OBD2 homepage. Any idea what a OBD2 code reader costs here in Canada?

Jana Banana · Post by **Jana Banana** » Mon Feb 19, 2007 12:50 pm

So I took it back to the shop to get the codes read again this morning. The same P0300 - random misfire code came up again and a new one, U1300 - Class 2 shorted to ground voltage. The tech didn't know what the U code meant..... I couldn't find anything online to explain it further for me. Anyone know? Could it be related to my power windows that work at random (mostly seem not to work during very wet weather)?

While the tech had it hooked up to the code reader he rev'ed the gas a little and it said both cylinders 1 and 6 misfired twice each...... So my van only has 1 coil, right? So it wouldn't seem the coil or EGR value are the problem or wouldn't all cyclinders be misfiring?

Further thoughts anyone?

astrozam · Post by **astrozam** » Mon Feb 19, 2007 1:03 pm

Jana Banana wrote: V8famvan on Astrosafari.com posted some good info on the exact codes from the OBD2 homepage. Any idea what a OBD2 code reader costs here in Canada?

If your getting some advice from V8famvan take note of what he advises,as he is a Master GM tech he knows his stuff.

I've seen OBD2 code readers range in price from $150 up,any auto parts store will have them. Good luck and keep us informed of what happens,zam

Jana Banana · Post by **Jana Banana** » Mon Feb 19, 2007 1:38 pm

Yes, they've been extremely helpful at astrosafari.com many times in the past =D> I'm cross posting on both forums right now because I figure the more info the better.......

I wanted to add a question I've come up with........

Could there be a vacuum leak or grounding problem causing #1 and #6 to misfire?

crash · Post by **crash** » Tue Feb 20, 2007 4:17 am

Jana.. keep an eye out for sales at Canadian Tire, they usually put the ODB2 readers on sale regularly. I will also pm you a price on one when I get to work. yes, I work at a parts store

edit: for some odd reason i can't find a listing through our distributor.

the good(?) news is that CT has them on sale at the moment.

Jana Banana · Post by **Jana Banana** » Tue Feb 20, 2007 6:47 am

Thanks for the info....... Not sure I can find $300+ right now after just having spent almost that on this tune up etc. Need to do the brakes too........ Ah, it's endless sometimes :-({|=

I will be purchasing one when the $$$ is there though........

PS Your parts supplier know anything about the EGR screen value by TomCo or other manufacturers? I had one put in on my last van (I do all city stop and go quick drives) to prevent carbon chunks from getting in there and it worked miracles - It went from stalling all the time (despite new EGR value, carbon flush and hours of attempted carbon clean out) to running perfect. Thinking I should invest in another one before this van gets badly carboned up. I only found one supplier in Ontario (can't remember who now - sure I can find the papers around here somewhere though) and he charged me an arm and a leg for it........

crash · Post by **crash** » Wed Feb 21, 2007 3:57 am

Yep.. we have the EGR screens .. let me get a part number and price today. They are not Tomco they are made by Standard. Same quality, and get this .. standard has been making them for years!

astrozam · Post by **astrozam** » Wed Feb 21, 2007 8:44 am

Would the part be the same for a 95 as well Rob (I think that's when they switched to the new style EGR) thanks

crash · Post by **crash** » Wed Feb 21, 2007 3:25 pm

here's what i was able to find out..

up to 91 was one style

92 was the year of the split when there were the W and Z motors with different EGR's

the screened EGR mounting gasket is for the W motor only and remained the same right up when they stopped production.

in 1993 the the Z motor w/ cali emissions used the EGR that was only for W motors in years prior.
the Z motor that was 'federally equipt' used the same Z motor EGR

confused yet? LOL

from 1994 onwards they are only listing what was known as the W EGR... now .. don't quote me on this and start yelling at me that I'm wrong.. I'm basing this on my parts supplier lookup.

in short.. the 1995 EGR is the same as the EGR from pre 1994 W .. so yes, .. anyone lost yet?

cdn price $23 + tax. and I could slap a stamp on an envelope and mail it regular post for .51 cents...

it looks like this

v8famvan · Post by **v8famvan** » Thu Feb 22, 2007 7:36 am

Jana, here is the code description for the u1300:

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition to this, Node Alive or State of Health messages are transmitted by each module on the class 2 serial data circuit about once every two seconds. When the module detects no messages and a low voltage on the class 2 serial data circuit for approximately three seconds, U1300 is set and the setting of all other class 2 serial communication DTCs is inhibited.

From personal experience I would recommend ignoring this code as this code can set by connecting up a scan tool. It is not related to your condition. The MIL light is flashing because it has detected or thinks is has detected a misfire. If you don't actually feel a misfire while driving (might need an experienced person to 'feel' this) I would recommend getting your CMP retard checked. (See post on AS for more info) If you do feel a misfire, it might be a seconday ignition problem - plugs, wires, cap, rotor, ect.
Note: I would recommend adding 'Rislone' to the engine oil. I have had great results with it. Frees up sticking valves on higher mileage engines.

Jana Banana · Post by **Jana Banana** » Thu Feb 22, 2007 1:37 pm

V8famvan - LOL! I just posted at AS! Thanks for the info on the U1300 - I was pretty much going to ignore it I figured - you might get a chuckle out of my little experience researching that code (story at AS). I think the CMP retard will be our next step there doesn't seem to be a noticeable misfire and all the rotor/cap, plugs, wires etc are all brand new now. I REALLY appreciate you sharing your knowledge and thoughts =D> . And I think I'll pick up some Rislone.

Crash - yup, you lost me! But I'm pleased to hear there's an available screen here in Canada under $50! That picture is exactly what the Tomco one looked like that I got, and it was applicable for years 1992-2002, so I'm sure it would fit your 1995 astrozam (I had it put in my previous 1995). Crash, can you send me a message with your work contact info so I can arrange to get one from you? TIA.

crash · Post by **crash** » Fri Feb 23, 2007 9:15 am

pm sent thanks Jana

Jana Banana · Post by **Jana Banana** » Fri Feb 23, 2007 2:22 pm

Thx crash, I emailed you.

Chevy & GMC Vans

Chevy & GMC Vans

Service Engine Light Flashing at 100km/h........

Service Engine Light Flashing at 100km/h........